1. Field of the Art
The present invention relates to a transition metal component of a so-called Ziegler type catalyst. According to the present invention, a catalyst component for polymerization of an olefin, which has a high activity and provides a polymer having a relatively large particle size, can be provided.
2. Description of the Prior Art
It has heretofore been known that, if a magnesium compound such as a magnesium halide, a magnesium alkoxide, hydroxymagnesium chloride or a dialkyl magnesium is used as a carrier component, a catalyst having a high activity can be obtained.
When a Ziegler type catalyst comprising this carried catalyst component or alternatively, a solid catalyst component, is used for polymerization of an olefin, an olefin polymer is obtained in the particulate form, but the particle size and particle size distribution of the obtained olefin polymer particles are influenced by the state of particles of the used solid catalyst component. In the olefin polymer particles formed, it is preferred that the particle size be relatively large and the particle size be uniform, because the productivity is increased by increase of the polymer concentration in the formed polymer slurry and facilitation of handling of the polymer slurry.
However, in the above-mentioned high-activity catalyst, it is difficult to control the particle size of the catalyst component, and in many cases, the average particle size is about 5 to about 10 microns and the particle size distribtuion of the catalyst is broad and is not satisfactory.
Accordingly, it is desired in the art to develop a process for preparing a catalyst in which the average particle size of the catalyst is relatively large and more than 10 microns and the particle size distribution can be controlled.
Related prior art techniques are disclosed, for example, in Japanese Patent Application Laid-Open Specifications Nos. 49-65999, 54-41985, 55-2951, 55-135102, 55-135103 and 56-67311.
According to these prior art techniques, a magnesium compound as the carrier component is finely divided or fused and is solidified by spray-drying granulation or rapid cooling. So far as we know, in order to increase the particle size of the catalyst in these known methods, large equipment investment is necessary, and it is considered that the particle size distribution of the formed catalyst is broad in these conventional techniques.